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On Aug 8 10:55, Joel Sherrill wrote: > On 8/8/2017 10:39 AM, Eric Blake wrote: > > On 08/08/2017 07:40 AM, Philipp.Trommler@preh.de wrote: > > > My impression is that you're in principle interested in having a fix > > > for the problem but you didn't have the resources to do it until now. > > > If this impression is right, I'd gladly provide a fix but I'll need > > > some advice from developers more experienced in newlib. > > > > > > So here are my questions: > > > > > > 1. Are you interested in a fix for the problem? If yes, what are the > > > steps that are necessary from your point of view? What are your > > > preferences for a possible implementation? > > > > Yes, we're interested. It sounds like any solution will have to be gated > > by compile-time conditionals around the typedef for time_t (so that > > embedded platforms don't have to pay the size penalties when they don't > > care about the larger range of time). Interesting. I would have answered the question with "No, we don't have that problem. Much." The newlib functions handling time_t are working fine with 32 and 64 bit time_t, so there's nothing to do to get 64 bit time_t functionality. Keep in mind that Cygwin is using 64 bit time_t on x86_64 for quite some time now. "Much", because the way time_t is defined is jusst a tad a bit unlucky: - time_t is generally typedef'ed to _TIME_T_, so that's good. - But _TIME_T_ is indiscriminately defined as long in sys/_types.h Only the latter aspect needs rethinking. In case of 32 bit Cygwin we also need to stick to a 4 byte type, unless "somebody(TM)" takes an interest and the time to change the Cygwin DLL to 64 bit time_t for 32 bit applications as well. Lots and lots of wrapping is required to keep older executables running. > I can't find the email in the rtems.org mailing lists but performance > is also an issue. I recall at least two CPUs where 64 bit math performance > was bad. I wouldn't overvalue that if only a few CPUs are affected. There's always a chance to improve the required math functions for those if the level of suffering gets too high. > That said, I think moving to 64-bit time_t is inevitable and > mostly overdue. I know RTEMS users have posted about fielding > systems with lifespans expected past 2038. ACK Corinna -- Corinna Vinschen Cygwin Maintainer Red Hat
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